Lecture 3 Flashcards
Wave transfer energy from one location to another in a __________ fashion
Cyclical
Mechanical wave need what two things to operate
A medium
And require physical interaction
Electro magnetic waves work in what 2 things
Medium or a vaccum
2 types of mechanical waves
Longitudinal and transverse
Sound waves are what type of mechanical waves
Longitudinal
What happens with the particles in longtitudinal waves
Particles vibrate back and forth
The vibration motion is parallel to the direction of travel of the wave
What happens with the particles in transverse waves
The motion is perpendicular to the direction of the wave
Along with mechanical and longitudinal sound waves can also be described as _______ and this means
Compressional, meaning has areas of particles closer together and areas far apart
Longitudinal waves are series of
Compression and rarefactions
Sound can also be described as
Travelling variation in acoustic variables
3 varying acoustic variables in sound
Pressure, density, and particle motion/vibration
As sound goes through a medium, ______ and _____ go through ______ of increase and decrease
Pressure and density
Cycles
Particles vibrate in
Oscillations
Two types of sound wave graphs
Pressure-time graph
Pressure- distance graph
Pressure time graphs will have peaks and troughs which correspond to
Compressions and rarefactions
What is a cycle?
One complete variation in pressure/density
Repetitive loops on wave graph have a ____ wave form
Sinusoidal
What is frequency
A measure of how often something happens over time
What is the audible range for humans
20Hz to 20kHz
Ultrasound frequency is
> 20kHz
What is period
Time it takes for one cycle to occur
If frequency increases, period __________
Decreases
What is wavelength
Physical length of one cycle
The cycle length
The speed of sound is called
Propagation speed/ acoustic velocity
The average propagation speed in soft tissue is
1.54 mm/us
Propagation speed is based on _____ only
The medium only
Bulk modulus is relating to the _______ of a medium
Stiffness
The more stiff the medium the _______ the propagation speed
Faster
